19 Ps 36.1 In whose heart is the oracle speaking?

The literal Hebrew is: An oracle (H5002) within (H7130) my (H589, personal pronoun me, mine, myself) heart (H3820).

These translations represent the oracle as speaking within the psalmist’s heart:

HCSB: an oracle within my heart

NIV84: an oracle is within my heart

YLT: is affirming within my heart

NKJV: an oracle within my heart

1890 Darby: uttereth within my heart

Geneva: even in mine heart

These translations represent the oracle as speaking within the wicked person’s heart:

ESV: transgression speaks to the wicked deep in his heart

NASB95: transgression speaks to the ungodly within his heart

AMP: transgression (like an oracle) speaks to the wicked deep in his heart

Given that “my” translates ʾ anî, a personal possessive pronoun, I judge that the first set of English translations is the correct interpretation.